Latch mechanism



Sept; l5, 1942. H. D. BREEN LATCH MECHANISM Filed Oct. 5, 1939 2Sheets-Sheet 1 INVENT OR. r'w. m

ATTORNEY ma man sa Heng gy.'

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Sept. 15, 1942. H. D. BREEN LATCH MECHANISM Filed oct. 5, 1939 2Sheets-Sheet 2 i INVENTOR. efafyreez/ Bw, Q #l :e a

ATTORNEY,

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Patented Sept. 1942 LATCH MECHANISM Henry D. Breen, Chicago, Ill.,assigner to Union Asbestos & Rubber corporation of Illino Company, is

Chicago, Ill., a

Application October 5, 1939, Serial No. I298,083

' the pawl, said control means in released position 10 Claims.

My invention relates in general to tensioning mechanism, and has moreparticular reference to tensioning means for vehicle brakes, especiallyrailroad car brakes.

An important object of the present invention is to provide improvedmanually-operable tensioning means for brake mechanism of the type inwhich a winding drum and associated holding pawl may be operated to winda exible tensioning member on the drum and retain the same in tensionedcondition, the mechanism being operable to cause the pawl to release thedrum for unwinding movement of the flexible member thereon.

A further object of the invention is to provide improved mechanismwhereby the apparatus may be conditioned so that the drum may bereleased by the pawl merely by manipulating the manually-operable drumtensioning member.

Another important object is to provide a manually-operable pawl controladapted to be arranged in a position normally holding the pawl inengagement with a cooperating ratchet-wheel, and in another position Vinwhich the pawl is held in position engaging the ratchet-wheel only solong as the ratchet-wheel maintains a thrust against the pawl; a furtherobject being to provide a composite pawl comprising a shiftable pawlcarrier and a pawl piece shiitable on the carrier in combination with apawl-controlling member cooperatively associated with both the carrierand the pawl piece and shiftable to selectively engage and release thecarrier and the pawl piece in order to control the same in the mannerheretofore mentioned.

Another important object is to provide a composite pawl comprising atiltable pawl carrier having a pawl mounted thereon for rocking movementbetween positions engaging and releasing av cooperating ratchet-wheel,including adjustable control means operatively associated with saidcarrier and the pawl to hold the carrier in one position with the pawlin operative relationship With the ratchet, and to yieldingly urge thepawl into engagement with the ratchet to prevent ratchet rotation in onedirection, said control means yielding to permit the pawl to release theratchet for rotation only in the other direction, said control meansbeing shiftable to an intermediate position holding the carrier inposition maintaining the operative relationship of the pawl and ratchet,from which intermediate position the control will drop, withoutmanipulation, to a releasing position upon turning the ratchet in adirection to release the thrust thereof upon permitting movement of saidcarrier in a direction to retract the pawl from the ratchet.

Another important object is to provide cooperating stops on the pawl andthe 4carrier to limit the turning movement of the pawl toward theratchet when the control is in the released position.

Another important object is to utilize a pawl control having a camcoacting with the pawl carrier to control the same; a further objectbeing to provide, on said control means and on said pawl, cooperatingabutments in predetermined relationship with respect to the cam for thecontrol of the pawl on the carrier.

Another important object is to utilize a pawl control comprisingrotatable means for engaging and controlling the pawl and its carrier,and a Weighted handle for controlling the movement of the rotatablecontrol means; a further objectbeing to provide for lost motion betweenthe rotatable control means and said handle; a still further objectbeing to provide for lost motion by means of interengaging abutments onthe handle and on the rotatable pawl and carrier engaging element.

A further object is to provide a simplified, automatic pawl controlmechanism particularly adapted for use in the winding mechanism oibrake-tensioning means such as are used in ve` hicles and particularlyrailroad vehicles whereby to allow the control handle to be moved to theon position, preventing unwinding movement of the winding mechanism,while allowing tensioning movement thereof, and to allow the controlhandle to be set in an intermediate position hold ing the windingmechanism in tensioned condition, the handle in its intermediate setposition being arranged to move automatically and without humanattention to a releasing position as a result 'of slight additionaltensioning on the winding mechanism, so that the brakemen need onlytighten the mechanism slightly, with the handle in its intermediate setposition, in order to release the brake-holding pawl.

These and numerous other important objects, advantages and inherentfunctions of the invention will become apparent as the same is morefully understood from the following description which, taken inconnection with the accompanying drawings, discloses a preferred form ofthe invention.

Referring to the drawings,

Figure 1 is a fragmentary view of the end of a railroad freight carhaving brake-tensioning means embodying my present invention;

Figure 2 is a sectional view taken substantially along the line 2-2 inFigure 1;

Figure 3 is a sectional View taken substantially along the line 3-3 inFigure 2;

Figure 4 is a sectional view taken substantially along the line 4-4 inFigure 3;

Figures 5, 6, '1 and 8 are enlarged fragmentary views of a portion ofthe device as shown in Figure 2, illustrating the several positions ofthe parts in operation; and

Figure 9 is an exploded view showing certain of the operating parts inperspective.

To illustrate my invention, IV have `show-non the drawings abrake-operating mechanism II e adapted for assembly as a unit inbrake-operating position, as on a railroad car I3. The brakeoperatingmechanism comprises cooperating elements forming a winding mechanism I2supported on a mounting which may and prefer-ably does comprise ahousing I4 for enclosing the winding mechanism and protecting the Ysamefrom the weather, as well as a frame of suflicient strength to carry theelementsy of the mechanism and sustain the stresses imparted thereto asa result of its operation. The winding mechanism is adapted to bemanually operated, as by means of a hand wheel I5, in order to tension aflexible element, such as a chain I1, which is connected to the brakerigging of the car in any suitable fashion. Y

In the illustrated Lembodiment the chain is attached to a draw-rodI91W-hCh inturn is connected to one arm of a tiltable bellcrankv 2'Icarried on the car I3 and connected tojtransfer the movement of thepull-rod I3`to a rodA 23 which is connected for operating the brakemechanism. Obviously, any preferred or equivalenty means may be utilizedfor transferring the drawing effect of the flexible tensioning elementI1 to the brake rigging, although it is preferable to utilize transfermeans adapted to multiplyT the brake applying force of the element I1. Y

The housing I4 may be of any suitableconstruction and is formed forattachment on the wall of the car I3. The casing preferably comprises ametal plate forming the back wall of the housing and having preferablyintegrallyformed marginal flanges 21 along its sides and top, providingside and top walls 'of the housing, and a removable cover 29 secured onthee'dgjes of the flange portions 21, as by the fastening means 3l, toform a front wall for the housing I4.

VThe back plate 25 also may have integrallyformed portions 32 providedwith perforations :i3V for the reception of bolts, rivets or Votherfastening means for the attachment of the device in mounted position onthe vehicle I3. The casing portions may be formed as metal castings oras drawn sheet-metal elements, in fact, the present invention is notnecessarily restricted to the form, construction or arrangement of theparts forming the casing. The casing, however, defines an opening 35 atits bottom end, through which the tension element I1 extends, the samebeing connected with the winding mechanism I2 which is mounted withinthe housing and bey tween the front and back walls 25 and 29.

Iny the illustrated vembodiment the winding mechanism comprises awinding drum III Yand a drum-driving gear 43, preferably formed as anelement integral with the drum/and comprising a hub carrying the drum 4Iand gear 43, and

adapted to receive a bushing 41 whereby to rotatably mount the elementon a shaft or pin 49. The opposed ends of the shaft are secured,respectively, in the back plate 25 and the cover 29, the same havingopenings preferably of noncircular configuration to receive thecorrespondingly congurated ends of the shaft 49.

The drum-driving gear 43 comprises a web 55 preferably extending in aplane intersecting the axis of the pin 49 at right angles, theperipheral edge of the Web 53 being formed with a rim carrying gearteeth 55.

The winding drum comprises spaced web portions 51 preferably formedhelically with respect to the axis of the bearing 41 to denne a helicalwinding space between the webs adapted to receive the tensioning elementI1, one end of which is attached to an anchor-pin 53 extending betweenthe webs 51 which are formed, as at 5I, to provide support lugs for theanchor-pin. Where a chain is used, as the tensioning element, theanchor-pin is assembled to the end link of the chain, as shown in Figure2 of the drawings, said link lying between the webs 51.

The winding drum also is formed with Webs 63 extending between the webs51 substantially radially with respect to the axis` of the shaft 43.These radially extending webs are for the purpose of strengthening thewebs 51 and to define pockets for receiving alternate links of thechain, including the end link which is anchored to the pin 59. Theremaining links of the chain lie upon the outer edges of the webs 51which are flattened to provide link-supporting surfaces extending atprogressively-decreasing distances measuring vertically from the axisoithe shaft 49, throughout the circumference of the winding drum, asclearly shown in Figure 2 of the drawings. The web 53 may be formed witha perforation 65 in alignment with the anchor-pin 59 in order tofacilitate the application of the anchorpin between the webs 51 of thewinding drum.

The drum-driving gear isdrivingly associated with a gear-driving'`pinion 61 which is mounted in the upper portions of the housing I@ Thepinion preferably is formed asan integral part of a rotatable spindle5i!V which is journalled for rotation in the back plate 25 andthe cover21, and carriesra ratchet 1I preferably formed on the stem 69 inintegral fashion. The pinion 61 is thus mounted in the housing inposition to drivingly engage with the toothed periphery of thedrum-driving gear d3, the4 ratchet 'II being arranged on the spindle 69substantially opposite the winding drum 4I.

The spindle 69 preferably has an integral, tapered end projectingthrough and outwardly of the front cover 29 of the housing, saidprojecting portion being preferably squared to receive a correspondinglysquared hub of the hand-*wheel I5 which is held in place on the spindleinany suitable or convenient means.

By turning the hand wheel I5, of course, the winding drum 4I may berotatedY to. draw the chain thereon by the driving engagement of thegear 43 and pinion 61. In order,however, to retain the mechanism intensioned condition, provide controlmechanism 1.3 preferably mounted onandsupported by the opposed back wall 25 and the cover 29 of thehousing. `This mechanism 13 comprises a pawl 15 tiltably mounted on apin11 which` ingturnis-carried on a pawl carrier 19.

The pawl 15.comprises a hub receiving the pin 11 and a projectingratchet-engaging nose 8I extending from the hub laterally in position toengage the ratchet 1| The pawl 15 is also formed with a preferablyintegral actuating finger 83'on the side of the hub opposite from thenose 8|, and a dependent projection 85 in position to engage ashoulder-forming portion 81 on the carrier 19. The carrier comprisespreferably a pair of spaced webs 89 preferably integrally formed on aspindle 9| by means of which the pawl carrier is rockingly mounted onthe back wall 25 and cover 29 of the housing.

'Ihe shoulder means 81 preferably comprises an integral web extendingbetween and interconnected with the webs 89, and said webs 89 providespaced journal openings 93 for receiving and supporting the pawlcarrying pin 11. 'I'he webs 89 are formed with cam-engaging surfaces 95in position to engage cams 91 comprising outstanding flanges formedpreferably integrally on a` shaft 99, which shaft is turnably mounted inand supported by the back wall 25 and cover 29 of the housing I4.

Between the lower portions of the cam flanges 91 and formed preferablyintegrally therewith and with the shaft 99 is a lip-like pawl actuatingprojection in position to cooperatively engage the pawl-actuating lug 83and urge the pawl on its carrier toward ratchet-engaging position whenthe shaft 99 is turned or urged in a counterclcckwise direction, viewingFigure 2 of the drawings. The shaft 99, on the side thereof oppositefrom the cams 91 and pawl-actuating lip |0|, is provided with apreferably integral counterweight |03 urging the element normally toturn about the axis of the shaft 99 in a direction to engage the lip |0|with the lug 83, to thereby move the nose 8| of the pawl into engagementwith the ratchet 1|.

The shaft 99 has an end |05 projecting outwardly of the housing cover29, said end having a portion |01 formed to receive a collar |09 havinga radially-projecting finger the shaft portion |01 being preferablysquared or otherwise formed to drivingly connect with the collar |09.The shaft 99, outwardly of the collar-carrying portion |01, is formedwith a portion ||3 adapted to rotatably receive a control handle whichmay be held in place on the shaft 99 in any suitable fashion, as bymeans of the holding nut ||1 applied on the threaded end portion ||8 ofthe shaft 99.

The control handle ||5 a bar having a hub ||9 at one end for receivingthe shaft portion H3, the opposite end of the bar being substantiallyweighted.

The hub ||9 is formed with abutments |2| and |23 in spaced angularrelationship in position to engage the opposite sides of the projectionon the collar |09, in order to urge the same and the shaftl 99, on whichthe collar is fixed, in one direction or the other, according to theposition of the weighted handle I5 on on-e side or the other of the axisof the shaft 99.

The angularity of the abutments |2| and |23 provide for lost motionbetween the control handle 5 and the shaft 99, whereby the cams 91 andthe lip |0| may remain in pawl-actuating position as the handle is movedfrom a pawlactuating position, through a substantial displacement,toward pawl-releasing position.

Referring more particularly to Figures 5-8, it will be noted that, whenthe parts are all in the pawl-actuating position shown in Figure 5, thehandle ||5 is in gravity-actuated position with the abutment |2|engaging the projection preferably comprises whereby to urge and retainthe cams 91 in abutting relationship with the cam following surfaces 95of the pawl carrier. The pawl carrier thus is positively held in thepawl-actuating position. At the same time, the lip |0I, under theinfluence of the weight |03 as well as the weight of the handle ||5, isheld against the lug 83 of the pawl, to thereby urge the pawl on its pin11 in a direction yieldingly engaging the ratchet 1|.

When the parts are in the position shown in Figure 5, therefore, thepawl engages the ratchet and prevents rotation thereof in thecounterclockwise direction, viewing Figures 2 and 5-8, that is to say,the pawl prevents unwinding movement of the winding mechanism and willhold the winding mechanism in tensioned condition. At the same time, asshown in Figure 6, the pawl 15 may rock on its pin 11 in the pawlcarrier 19, if the ratchet is rotated in the clockwise direction toadditionally tension the winding mechanism. Rocking movement of thepawl, under such circumstances, will merely depress the lip |0| and turnthe shaft 99 in a direction to slightly elevate the weighted handle H5,but without turning the shaft 99 sufficiently to disengage the cams 91from the surfaces 95 or release the pawl carrier from actuatingposition.

The handle 5, however, while the pawl and its carrier remain inratchet-holding position, may be rotated to the intermediate,substantially-vertical position shown in Figure '1, in which theabutment |23 of the handle is in engagement with the shaft projectionI||. When in such intermediate position, the weighted handle |I5 is onthe side of a vertical plane through the shaft 99 opposite from theposition occupied by the handle in the pawl-holding position shown inFigures 5 and 6; but the cams 91 and the lip |0| remain inpawl-actuating and holding position due in part to the effect of thecounterweight |03, unless and until the back thrust of the ratchet uponthe nose 8| of the pawl is relieved, as when the hand wheel I5 is turnedin a direction slightly to increase the tension on the element |1 and torelieve the thrust of the ratchet upon the pawl.

When thrust is thus relieved, the frictional engagement between the cams91 and the follower surfaces 95 is reduced, so that the weight of thehandle ||5 becomes eifective to cause rotation thereof and of the shaft99 to the position shown in Figure 8, wherein the cams 91 have beenwithdrawn from carrier-holding position, and the lip I0| has beenwithdrawn from the lug 83. 'Ihe carrier 19 thus is free to rotate incounterclockwise direction about the axis of the stern 9| to a positionfreeing the pawl from the ratchet and permitting the ratchet to turn ina direction allowing the drum to unwind the element I1, the cooperatingstops and 81 on the pawl and carrier being designed to prevent the noseof the pawl from dropping to an inoperative position on the carrier whenthe parts are in ratchetreleasing condition.

It will be seen from the foregoing that I have provided a simple andinexpensive construction comprising a plurality of integral and ruggedparts which at the same time allow the facilities and advantages of pawlcontrol hereinbefore described, including the ability of holding thepawl yieldingly in actuating position, allowing the ratchet to turn inone direction but preventing turning movement in the time allowing themechanism to be conditioned, as indicated in Figure 7, so that thewinding other, and at the same' the form, construction and arrangementof the several parts without departing from the spirit or scope of theinvention or sacrificing any of its attendant advantages, the formVherein shown being merely for the purpose of disclosing the invention.

The invention is hereby claimed as follows:

1. The combination, with a ratchet, of pawl means and pawl control meansoperable to govern the interaction of the pawl means and ratchet, saidpawl means comprising a shiftable pawl carrier and a ratchet detentshiftable on said carrier, and said pawl control means being biasednormally to hold the carrier in a predetermined operating position andbeing movable into position releasing the carrier whereby to permit thedetent to be retracted from the ratchet, said control means being alsomovable into position retaining said carrier in said operating positionand to yieldingly urge said detent on said carrier toward operativeengagement With said ratchet.

2. The combination, with a ratchet, of pawl means and pawl control meansoperable to govern the interaction of the pawl means and ratchet, saidpawl means comprising a rockable pawl carrier and a ratchet detenttiltable on said carrier, and said pawl control means being biasednormally to engage said carrier and retain the same in a predeterminedoperating position, said control means being movable into positionreleasing the carrier for rocking movement from said operating positionwhereby to permit the detent to be retracted from the ratchet, saidcontrol means being also movable into position retaining said carrier insaid operating position and to yieldingly tilt said detent on saidcarrier toward operative engagement with said ratchet when the carrieris in operating position.

3. The combination, with a ratchet, oi pawl means and pawl-control meansoperable to govern the interaction of the pawl means and ratchet, saidpawl means comprising a shiftable pawl carrier and a ratchet detentshiftable on said carrier, and said pawl control means comprising amember movable into position engaging and retaining the carrier in apredetermined operating position and yieldingly urging said detent onsaid carrier toward operative engagement with said ratchet, said memberbeing disposable in position releasing the carrier for movement awayfrom operating position to thereby retract the detent from the ratchet.

4. The combination, with a ratchet, of pawl means and pawl control meansoperable to govern the interaction of the pawl means and ratchet, saidpawl means comprising a shiftable pawl carrier and a ratchetdetentshiftable on said carrier, said pawl control means comprising aturnable member having an abutment in position to hold the carrier in apredetermined operating position when said turnable member is in apredetermined angular position, means on said turn.-

assegni able member in position'engaging said detent, and biasing meansconditionable normally to yieldingly urge said turnablemember in adirection to bias the detent'toward ratchet engaging position. f

5. The combination, with a ratchet, of pawl means and pawl control meansoperable to govern the interaction of the pawl'means and ratchet; saidpawl means comprising a shiftable pawl carrier and a ratchetdetent'shiftable on said carrier, said pawl control means comprising aturnable member having an abutment in position to hold the carrier inaVpredetermined operating position when said turnable member is in apredetermined angular position, means on said turnable member inposition engaging said detent, and biasing means conditionable normallyto yieldingly urge said turnable member in a direction to bias thedetent toward ratchet engaging position, said biasing means beingconditionable to urge the turnable member in a direction to release saidcarrier for movement away from operating position to permit retractionof the detent from ratchet engaging position.

6. The combination, with a ratchet, of pawl means and pawl control meansoperable to govern the interaction of the pawl means and ratchet, saidpawl means comprising a shiitable pawl carrier and a ratchet detentshiitable on said carrier, said pawl control Vmeans comprising aturnable member having an abutment in position to hold the carrier in apredetermined operating position when said turnable member is in apredetermined angular position, means on said turnable member in`position engaging said detent, and biasing means conditionable normallyto yieldingly urge said turnable member in a direction to bias thedetent toward ratchet engaging position, said biasing means beingconditionable to urge the turnable member in a direction to release saidcarrier for movement away from operating position to permit retractionof the detent from ratchet engaging position, said biasing meanscomprising a Weighted lever, and means drivingly connecting said leverwith said turnable member.

7. The combination, with a ratchet, of pawl means and pawl control meansoperable to govern the interaction of the pawl means and ratchet, saidpawl means comprising a shiftable pawl carrier and a ratchet detentshiftable on said carrier, said pawl control means comprising a turnablemember having an abutment in position to hold the carrier-in apredetermined operating position when said turnable member is in apredetermined angular position, means on said turnable member inVposition engaging said detent, and biasing means conditionable normallyto yieldingly urge ysaid turnable member in a direction to bias thedetent toward ratchetl engaging position, said biasing means beingconditionable to urge the turnable member in a direction t0 release saidcarrier for movement away from operating position to permit retractionof the detent from ratchet engaging position, said biasing meanscomprising a weighted lever, and means comprising a lost motionconnection drivingly connecting said lever with said turnable memberwhereby 'the turnable member may remain in carrier holding positionV as'said lever is shifted from operating position on one side of thevertical plane through its axis of rotation to an intermediate positionon the other side of said plane in position to move the turnable memberto carrier releasing position upon Withdrawal of the thrust of theratchet on said detent.

8. In combination, with tensioning mechanism comprising a Winding drum,means for turning the same to draw a flexible tension element thereon,and a ratchet drivingly connected with said drum, of holding meansoperatively associated with said ratchet and comprising pawl means andpawl control means operable to govern the interaction of the pawl meansand ratchet, said pawl means comprising a shiftable pawl carrier and aratchet detent shiftable on said carrier, and said paWl control meansbeing adapted normally to hold the carrier in a predetermined operatingposition and being selectively operable to release the carrier to permitretraction of the detent from the ratchet, or to retain said carrier insaid operating position and to yieldingly urge said detent on Saidcarrier toward operative engagement With said ratchet.

9. In combination, with tensioning mechanism comprising a winding drum,means for turning the same to draw a flexible tension element thereon,and a ratchet drivingly connected with said drum, of holding meansoperatively associated with said ratchet and comprising pawl means andpawl control means operable to govern the interaction of the paWl meansand ratchet, said pawl means comprising a shiitable pawl carrier and aratchet detent shitable on said carrier, and said pawl control meanscomprising a turnable member having an abutment in position to hold thecarrier in a predetermined operating position when said turnable memberis in a predetermined angular position, means on ber in positionengaging said detent, and biasing means conditionable normally toyieldingly urge said turnable member in a direction to bias the detenttoward ratchet engaging position, said biasing means being conditionableto urge the turnable member in a direction to release said carrier formovement away from operating position to thereby permit retraction ofthe detent from ratchet engaging position.

said turnable mem- V.

10. Tensioning mechanism for Vehicle brake rigging comprising anenclosing housing and winding mechanism Within said housing comprising aWinding drum, means to turn the same to draw upon said drum a flexibletension element connected Wit-h the brake rigging, a ratchet drivinglyconnected With said drum and turnable in response to the movementthereof, pawl means comprising a shiftable pawl carrier and a ratchetdetent shiftable on the carrier and operatively associated With saidratchet, and paWl control means, said pawl control means being adaptednormally to hold the carrier in a predetermined loperating position andbeing selectively operable to release the carrier to permit retractionof the detent from the ratchet, or to retain said carrier in saidoperating position and to yieldingly urge said detent on said carriertoward operative engagement with said ratchet, said pawl control meanscomprising a turnable member having an abutment in position to hold thecarrier in a predetermined Operating position when said turnable memberis in a predetermined angular position, means on said turnable member inposition to engage said detent, and biasing means conditionable normallyto yieldingly urge said turnable member in a direction to bias thedetent toward ratchet engaging position, said biasing means comprising aweighted lever, and means drivingly connecting said lever With saidturnable member, comprising a lost motion connection Whereby the membermay remain in carrier holding position as said lever is shifted fromoperating position on one side of the vertical plane through its axis ofrotation to an intermediate position on the other side of said plane inposition to urge the turnable member toward carrier releasing positionto thereby release the carrier upon Withdrawal of the thrust of theratchet on said detent upon turning the drum in a direction to increasetension on said flexible tension element.

HENRY D. BREEN.

